Performance and Profitability Simulation of Crops under Different Managements of Irrigation Water Using System Dynamics Approach

One of the agricultural development strategies is to establish irrigation and drainage networks that will lead to higher productivity and greater economic benefits. In the present study, by using system dynamics approach, a computer model was developed that can estimate the crop yield of an irrigation network according to the quantity and quality of simulated irrigation water and to estimate the net profit of the products. In order to calibrate and validate the model results, the data collected from the research lands of the right side of Abshar Irrigation Network were used. After statistical analysis and calculation of RMSE, relative error, the standard error, and correlation coefficient, adjustment between the measured and simulated network products performance was calculated. The value of these product indexes according to the conditions of the network was estimated as 209.98 kg/ha, 1.36 percent, 0.007, and 0.99, respectively. The results showed that the model had reasonable accuracy in simulation of the irrigation network, its cropping pattern, and definition of other scenarios. Also, an initial check showed that groundwater exploitation in the mentioned area was more than the permitted limit. Considering the importance of water resources, two scenarios were defined i.e. irrigation according to water requirement of crops and irrigation based on limitation of exploiting groundwater resources. Analysis of the results showed that the average of the products income to cost ratio for irrigation of the network in 2006-2007, the first scenario, and the second scenario was, respectively, 2.58, 2.88, and 2.75.